In a conventional manner, nail polishes contain the following as primary components: organic or aqueous solvents, at least one film-forming compound and a plasticizer, pigments and/or coloring compounds. For several years, efforts have been made to formulate compositions for nails without either phthalates or condensation products of acetaldehyde, compounds that have proven hazardous to health. It is therefore desired to develop new plasticizers that are less toxic and/or less volatile.
Furthermore, the current tendency, in all of the sectors, and in particular in the field of cosmetics, is increasingly to turn to so-called natural products, in particular products derived from plant substances.
The formulator, however, is confronted with many difficulties and constraints. Actually, each change in component or each modification of the concentration of a component has an effect on the properties that are desired for the polishes, such as adhesion, gloss, and hardness, but also flexibility.
For example, for several years, acetyl tributyl citrate (ATC) (cited in particular in U.S. Pat. No. 5,227,155) almost exclusively replaced the phthalates that were initially used as plasticizers. It was observed, however, that ATC imparts lower gloss to the polish than the phthalates.
Furthermore, it was noted that certain so-called natural plasticizers promote either an uptake of water of the polish, i.e., they have the drawback of leading to, after the polish dries on the nail, an absorption of water (for example when the individual bathes, washes or has her hands in water for household activities . . . ) or a degradation by migration in the water of the hydrophilic components of the polish; this is the case of, for example, carbonate-based plasticizers, such as glycerol carbonate (WO2007/080172). This water absorption that causes a swelling of the polish, or this degradation, leads to a reduction of its strength and a loss of adhesion. These consequences are very detrimental to keeping the polish on the nail.
There have been similar findings with nail polishes that contain ATC in areas with high hygrometry. These polishes exhibited adhesion defects, which have turned out to be caused by the absorption of ambient moisture.